With the progress of computer graphics technology in recent years, picture processing devices, such as game devices and simulation devices, which are capable of displaying images in a three-dimensional space have been provided. Display objects (or characters) on displaying means are composed of polygons. Polygons herein used mean polygons (mainly triangles or quadrangles) which are made of an aggregate of plural vertexes.
A conventional picture processing device has limitations on the number of polygons handled by its central processing unit (CPU). Accordingly, a character located far away from a viewpoint is composed of a small number of polygons, while a character located close to the viewpoint is composed of a large number of polygons because the pattern and shape of the character have to be realized in detail (First Prior Art Example).
Moreover, a character in, for example, a soccer game is sometimes expressed with polygon data to which a texture mapping is applied. In this case, textures with players' numbers written for each different team uniform are prepared as many as the number of players (Second Prior Art Example).
Furthermore, in a conventional picture processing device, characters on a screen of displaying means are displayed with the same brightness regardless of the distance from a viewpoint (Third Prior Art Example).
In addition, when characters composed of polygons are displayed by a conventional picture processing device, a virtual viewpoint (or camera) is prepared in a three-dimensional coordinate system and an image of these characters taken by this viewpoint are displayed. In order to diversify the three-dimensional display of the characters, a plurality of cameras are prepared as in a game called “Virtua Fighter” and these cameras are switched to display the characters on the displaying means (Fourth Prior Art Example).
In the case of a game device (or picture processing device) of a soccer game, when a player which is a related display object turns around to protect a ball, which is a specific display object, and proceeds to the next action, it is necessary to operate an operation terminal in order to make the positions of the ball and the player coincide with each other (Fifth Prior Art Example).
Moreover, in the case of a conventional game device, details of general operations of an operation terminal are previously indicated on a housing (Sixth Prior Art Example).
In the First Prior Art Example, as explained above, a character far away from a viewpoint is always composed of a smaller number of polygons than those of a character close to the viewpoint. Accordingly, when a player (or character) which receives a pass in a soccer game attracts a game player's attention, for example, if the player is far from the viewpoint and is a character composed of a small number of polygons, the player is expressed merely in a monotonous shape and pattern. With this type of game device, the game player's attention is lowered and the game lacks a delicate taste. Such a game device is poorly attractive to consumers.
In the Second Prior Art Example, data with the aforementioned texture mapping applied should be prepared for all players. The priority of polygons is generally decided based on which polygon is located further back (in a z-axis direction). In this case, however, both the uniform and the player's number are located at the same position. Therefore, it is impossible to always place the player's number over the uniform with certainty by simply laying one over another. If a flag control is utilized to always set the player's number over the uniform, even if the player faces front and the player's number should not be seen, the player's number is placed over the uniform. Accordingly, there is no way but to prepare a texture of the uniform with the player's number written, knowing that the data volume will increase. This imposes a considerable computation load on CPU and, therefore, there is a possibility that the processing of CPU may be delayed, thereby diminishing a realistic excitement of a game. Otherwise, if a CPU capable of processing a large computation load is adopted, it costs too much.
In the Third Prior Art Example, since the characters are displayed with the same brightness regardless of the distance from a viewpoint, a game player cannot experience a feeling of far and near sufficiently.
In the Fourth Prior Art Example, even though there are a plurality of cameras, the positions of these cameras are fixed. Therefore, diversification of image expression cannot be fully achieved. Particularly, for a game such as a soccer game in which a player who takes control over a ball changes every moment and the superiority of the game accordingly changes in an instant, there is an disadvantage in that a full view of the game cannot be displayed effectively if the viewpoints are fixed.
In the Fifth Prior Art Example, a high-grade operation is required in order for a player to control a ball effectively. For this purpose, a game player needs to become fully skillful in the operating means of the game. It is difficult for an unskillful game player to control the game in order to have a player control a ball tactfully.
In the Sixth Prior Art Example, it is impossible to indicate the content of all the operations on a housing, depending on the content. If the content of all the operations should be indicated on the housing, it is difficult for the game player to read and memorize it in advance.
In conclusion, any of the above prior art examples provides poorly interesting expressions of characters and the characters are expressed insufficiently in relation to the operational performance.
Accordingly, an object of the present invention is to provide a picture processing device which is capable of richly expressing a displayed picture including the display objects (such as characters and background) of the above-described prior art examples, and of controlling the display objects diversely in relation to the operation.
A second object of the invention is to provide a picture processing device which is capable of realizing a detailed shape and pattern of a display object which attracts a game player's attention even when the display object is far away from a viewpoint.
A third object of the invention is to provide a picture processing device which is capable of displaying many display objects with a small computation load.
A fourth object of the invention is to provide a picture processing device which is capable of realizing the far and near expression in a displayed picture effectively.
A fifth object of the invention is to provide a picture processing device which is capable of displaying a full view of the results of the picture processing effectively.
A sixth object of the invention is to provide a picture processing device which is capable of smoothly controlling and displaying the movement of a related display object in relation to a specific display object without any special skill required.
A seventh object of the invention is to provide a game device which is capable of giving only a minimum necessary description to a housing, and of displaying other operating methods of a operation terminal in an easily recognizable manner.